Resilient ball retainer for tooth and holder



Oct. 14, 1969 G. L. SPIVEY 3,471,954

RESILIENT BALL RETAINER FOR TOOTH AND HOLDER Filed July 18, 1966 INVENTOR. azpaw Z, .S'P/Vi/ BY w United States Patent 3,471,954 RESILIENT BALL RETAINER FOR TOOTH AND HOLDER Gordon L. Spivey, Oklahoma City, Okla., assignor to Construction Machinery, Inc., Oklahoma City, Okla. Filed July 18, 1966, Ser. No. 566,120 Int. Cl. E041? 9/28; F16b 7/00 U.S. Cl. 37-142 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a new and improved ball retainer for tooth and holder. More particularly, the invention relates to a combination of a tooth of the type used in excavating equipment, a tooth holder therefor, and a ball partially received in a recess in the holder and projecting therefrom, which engages a surface of the tooth received in the holder, is deformed by the force of insertion of the tooth and is sufliciently resilient so that it fits into a depression in the tooth to serve as a detent. Thus, the ball serves to restrain the tooth from unintentional dislodgment from the holder.

A particular feature and advantage of the invention is the fact that the ball can be used repeatedly to perform its retaining function. This feature of the ball arises out of the fact that after it has been used once it may be rotated slightly and a different portion of its surface then serves to contact the tooth. Accordingly, although the ball is somewhat deformed after each use, the area of the ball which is so deformed is small compared with its over-all area thereby permitting a new portion of the surface to be presented each time the ball is used.

Accordingly, the present invention provides a convenient means for retaining a tooth in its holder which may be used repeatedly and is as effective each time it is used as the preceding times.

In the structure hereinafter described in detail, there is provided a tooth having a distal portion of a broad, flat spade-like shape and having a proximal portion of lesser cross section. The holder has an enlarged outer end formed with a recess complementary to the proximal portion of the tooth. A bore is formed in one wall of the recess and a ball fits in the bore and its top projects into the recess. The ball may be formed of nylon or other hard but resilient material. Preferably, the bore is larger than the ball to accommodate deformation thereof. A preferred form to accomplish this result is to form the bore with a semi-spherical bottom complementary to the ball and a short cylindrical section above the semi-spherical bottom. The back end of the tooth is slightly relieved to permit the back end of the tooth to fit over the exposed top of the ball. As the tooth is forced ino the holder, the ball deforms to permit passage of the tooth past the ball. However, a depression is formed in the surface of the tooth which is immediately opposite the bore when the tooth is fully seated in the holder and by reason of the resilient nature of the ball, it fits into the depression and serves to lock the tooth in place against unintentional displacement. Provision is made for driving the tooth out of the holder when it is necessary to change or sharpen the same, the ball likewise deforming to permit this operation. During the installation of the tooth the ball is deformed and truncated at the exposed top. When the ball is re-used, it is turned so that a new surface is presented each time the ball is used.

Accordingly, it is a principal purpose of the present invention to provide a resilient ball retainer which normally securely retains the tooth in its holder but which can be deformed by pressure applied from an external source so that the retainer is disengaged.

A further feature of the invention is provision of a tooth having at its distal portion rearwardly-centrally slanted surfaces which mate with cooperating surfaces on the forward end of the tooth holder to limit inward movement of the tooth relative to the holder and also to cooperate in holding the tooth in alignment relative the holder.

Oher objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which sismilar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIG. 1 is a. top plan view of the tooth and a portion of the holder.

FIG. 2 is a longitudinal vertical sectional view taken substantially along the line 2-2 of FIG. 1.

FIG. 3 is a fragmentary sectional view showing a preliminary step in the insertion of the tooth in the holder.

FIG. 4 is a view similar to FIG. 3, showing a further step in the insertion of the tooth.

The present invention has particular application in excavating machines (not shown) of a type commercially available used in smoothing roadway surfaces preparatory to paving. In such machines there is provided a rotating shaft which is horizontally-transversely disposed and power driven, having radial members (not shown) to which the holders 11 of the present invention are applied as by welding, bolting or other convenient means. For such purpose the underside of holder 11 is provided with a step 12 having a forward shoulder 13 for attachment purposes. Forwardly of shoulder 13 the underside of holder 11 is formed with an enlarged bottom portion 14. Extending above the top of the rearward stem 16 of holder 11 are side portions 17 and the side portions 17 are interconnected at the front end of the holder 11 by a top portion 18 which extends transversely therebetween. An aperture 19 is formed centrally in top portion 18 in order to insert the ball as hereinafter described. Between top portion 18 and bottom portion 14 is a recess 21 which is generally rectangular in cross-section. In the bottom wall 22 of recess 21 and extending into bottom portion 14 is a centrally disposed cylindrical bore 23 having a spherical bottom 24. Knock-out hole 20 extends out the bottom. Rearwardly of top portion 18 is an opening 25 through which an instrument may be inserted to drive the tooth out of the recess when required.

Tooth 26 is formed with a distal portion 27 and a proximal portion 28. Distal portion 27 has sidewardlyoutwardly diverging vertical side edges 30 which terminate in a blunt transverse forward cutting edge 29 having a width slightly greater than that of holder 11. Top surface 31 slants downwardly-forwardly as viewed in FIG. 2 and the central bottom surface 32 tapers forwardly toward front edge 29. Because of the wear of the front corners and the susceptibility of such corners to be broken off, bottom surface 32 is provided with relatively narrow side ribs 33 which coverge forwardly toward front edge 29. Bottom surface 32 curves as indicated by reference numeral 34 adjacent the rearward end of the distal portion so that there is a substantial thickness of material in the back of the distal portion. The back surfaces 36, 37 of the distal portion angle rearwardly-inwardly and the forward end of holder 11 is likewise formed with angular inward-rearward surfaces 38, 39 mating with surfaces 36, 37, respectively. The shape of the cooperating rear surfaces of the tooth and forward surfaces of the holder limit inward movement of the tooth relative to the holder and also tend to hold the tooth in alignment relative to the holder and to the machine in which it is installed.

Proximal portion 28 of the tooth is of lesser width than distal portion 27 and has parallel vertical side edges 41 spaced apart approximately half the distance between edges 30. The bottom 42 of portion 28 is fiat through most of its area. However, a depression or dimple 43 is formed therein in registry with bore 23 in the assembled position of the tooth and holder. Further, the bottom back edge is relieved as indicated by reference numeral 44 for a purpose which hereinafter appears. Top surface 45 is generally flat and fits against the top wall of recess 21. Rearward end 48 is fiat and transverse.

The retainer to hold the tooth in the holder is a ball 51 which fits in bore 23 and rests on spherical bottom 24 with its top portion projecting above surface 22. Ball 51 may be formed of nylon or other relatively hard suitable material and is of a commercially available type used in various industries.

The proximal end 28 of tooth 26 is inserted in recess 21 with ball 51 in place. Insertion of ball 51 may be accomplished by dropping it through opening 19 or by inserting it through the front of the recess 21. As the back edge 48 moves rearwardly, it encounters the top exposed portion of ball 51 and the relieved portion 44 fits over the top of ball and serves as a ramp so that as the inward movement of the tooth continues to the position shown in FIG. 4, the ball 51 is squeezed and deformed in bore 23 and partially bent back in a tip 52 which is squeezed into the clearance between the proximal portion of the tooth and the recess 21. When the tooth reaches its fully inserted position as shown in FIG. 2, by reason of the resilient nature of ball 51, it at least partially returns to its original position and thus at least partially fills depression 43. The ball 51 thus serves to lock or keep the tooth in the holder. As shown in FIG. 2, the top of the ball as indicated by reference numeral 53 is somewhat deformed, part of the displaced material appearing in the tip 52. The extent of the total surface area of the ball which is thus deformed is relatively small and hence the ball may be re-used repeatedly by merely turning it in bore 23. It has been found that although ball 51 is deformed, little if any material is 'actually shaved 01f.

When it is necessary to remove the tooth, an instrument may be inserted through the back opening and driven against the back end 48. During such operation, the ball 51 again deforms. The ball may be unseated by probing through hole 20, then turned in seat 24 to expose a different part of its surface.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes of clarity and understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In combination, a tooth having a distal portion formed with at least one cutting edge and a proximal portion, said proximal portion being generally rectangular in cross-section and having a longitudinally extending first surface, a tooth holder having a forwardly-opening recess shaped generally complementary to said proximal portion and having a longitudinally extending second surface in proximity to said first surface, said first surface being formed with a dimple-like depression and said second surface being formed with a bore in registry with said depression; said bore being cylindrical at its outer end and hemispherical at its inner end, the back end of said first surface being formed with a central relieved area, and a retainer shaped in a ball, said ball being partially in said bore and having its top projecting beyond said second surface, said retainer being of a radius about equal to that of said hemispherical end of said bore, said retainer fitting in said depression in the assembled position of said tooth and holder to restrain unintentional dislodgement of said tooth, said retainer in the assembled position of said tooth and holder being resiliently squeezed and deformed and bent backward in a tip squeezed between said first and second surfaces, the relieved area of said back end of said first surface facilitating commencement of deformation of said retainer to permit insertion of said proximal portion in said recess, the top of said retainer being deformed with a fiat surface, the extent of said flat surface being substantially less than the extent of projection of said retainer above said second surface, said retainer also being deformable to permit withdrawal of said proximal portion from said recess, said retainer being rotatable within said recess when said proximal portion is removed from said recess to permit different portions of the surface of said retainer to be exposed above said second surface each time said retainer is used.

2. The combination of claim 1 in which said holder is formed with a hole in the surface opposite said second surface.

3. The combination of claim 1 in which said proximal portion is narrower than said distal portion and the top and bottom of the rearward end of said distal portion to either side of said proximal portion slants downwardinward, the forward face of said holder shaped complementary to said rearward end to limit inward movement of said tooth relative to said holder and hold said tooth in alignment with said holder.

References Cited UNITED STATES PATENTS EDGAR S. BURR, Primary Examiner US. Cl. X.R. 299-92 

